The increase in violent crime has had a large and adverse influence on the retail merchant. The availability of currency, even in small quantities, in the cash register of the retail merchant has made him perculiary vulnerable to the unpredictability of the amateur thief and the driving need of the narcotics addict. Retail merchant robberies consequently has an unfortunate record of violence and fatality. "Exact change" policies sometimes coupled with a locked safe, and "credit card only" policies have had notable success in completely halting robberies of bus drivers and service station operators. This success has been at the serious cost of customer convenience and lost business.
Robberies occur only when the thief believes that he has a good chance of getting money and avoiding apprehension and punishment. A number of attempts have been made to make retail robbery less profitable. The familiar slow frame film camera in banks and retail stores has had a beneficial effect. Unfortunately, since these cameras must operate continuously, the need to conserve film has limited their frame rate to a few frames per minute. Many of the details of a robbery transaction are lost in this type of snapshot approach. In addition, the pictures provide only a historical record of the event aiding in identification and prosecution of the perpetrators. There is no provision for summoning assistance while the robbery is in progress to improve the probability of apprehension in the act.
U.S. Pat. No. 3,596,024 in the name of Floyd Smith taught a floor pressure switch which initiated a radio distress call from a recorder. This system required radio receiving equipment at the police station or the office of private security agents. In addition, no provision was made for recording events of the robbery transaction to aid in identification and apprehension of the perpetrators.
U.S. Pat. Nos. 3,678,509 and 3,707,708 in the name of Carlo Dan, teach the use of dedicated telephone lines from the protected premises to a central monitor station. When an intrusion or holdup alarm is generated at the protected premises a reversal in the DC signal previously maintained on the dedicated lines initiated on alarm signal at the central monitor station. Neither of the cited patents dealt with storing data for later use. The cost of dedicated lines and a central monitor station takes this system outside the means of the average merchant.
The prior art fails to teach a low-cost system for triggering a holdup alarm, summoning assistance while the holdup is in progress, and recording audible and/or visual details of the time period centered on the alarm time.